Externally-heatable ignition plug



A. PETER. EXTERNALLY HEATABLE IGNITION PLUG.

APPLICATION FILED JUNE 1. I920.

Patented May 30, 1922.

UNITED. srA-ras rareur OFFICEQ ALFRED PETER, OF BEIAOIT, WISCONSIN,ASSIGNOR TO FAIRBANKS, MORSE &'CO., OF CHICAGO, ILLINOIS, A CORPORATIONOF ILLINOIS.

EXTERNALL Y -I- IEATABLE IGNITION PLUG.

Application filed June 1,

To all whom it may concern:

I Be it known that I, ALFRED ln'rnn, a citizen of the United States,residing at Beloit, in the county of Rock and State of Wisconsin, haveinvented a certain new and useful Improvement in Externally-HeatableIgnition Plugs, of which the following is a specification.

This invention relates to ignition plugs for internal combustion enginesof the class such as a kerosene oil engine, which requires an externalheating device at starting, but thereafter fires itself. An engine ofthis type is shown in Hobart & Jahnke Patent No. 1,159,341, issuedNovember 2, 1915.

The object of this invention is to provide a device of this charactercarrying an externally heatable electric resistance coil which is sosimply constructed as to be readily insertable and removable in the wallof the engine and in which the plug itself can be quickly taken apartfor replacement of one or more parts, particularly the resistance orheating coil. 7

The invention consists in means for carrying out the foregoing objectswhich can be easily and cheaply made and installed, which issatisfactory in use and is not readily liable to get out of order. Moreparticularly the invention consists in features and details ofconstruction more fully set forth in the specification and claims.

Referring tothe drawings in which simi lar numerals represent the sameparts throughout the several views,

Figure'l is a sectional detail view of the mechanism illustrating thisinvention in its preferred form as it appears applied to the tophorizontal wall of an engine cylinder.

Figure 2 is a plan view of the plug itself as seen in Figure 1, theelectric circuit at the top of that figure being omitted.

As shown in the drawing, the plug body 16 is applied through the agencyof screw threads 10, to an engine wall 12, shown in conventional form,provided with a water jacket space 14. The portion of the plug body 16which remains outside the engine wall is provided with a non-circular,in the particular case here illustrated hexagonal, circumferential wall18 adapted to be engaged by an ordinary wrench for obvious purposes.

Extending through this plug 16 is'a cylindrical member 20 carrying atits smaller end Specification of Letters Patent.

Patented May '30, 1922. 1920. Serial No. 385,595.

screw threads 22 and having on its other end an enlargement orshouldered head 24 which takes bearing on insulating washers 26 throughwhich the smaller portion of the screw passes. The member 20-24 will forconvenience be referred to as a core. The end of member 16 which istoward the inside of the engine is bored outin a relatively large recess28 against whose inner end, here.- after referred to as shoulder 25, thewasher 26 takes bearing. This recess 28 is of sufficient size so that itprovides an insulating air space all around the head member 24 of thecore, heretofore referred to. The remainder of the central portion ofblock 16 not occupied by recess 28 is occupied by a continuing, butsmaller, perforation 29 of such a size that it provides an insulatingairspace around the smaller portion 20 of the core. Slidahlv mounted onthe outer end of this member 20 and closing the open outer end of recess29 is an insulating washer 30 over which is placed an ordinary metalwasher 32 held in place by a nut 34 traveling on screw threads 22 onmember 20 in the ordinary manner.

From the foregoing it will be seen that nut 34 detachably fastens thecore member 26-24 inside of the plug body 16 in insulated relationtherewith. The portion 20 of the core is made of sufficient length sothat it extends considerably beyond the outer end of plug body 16, aboveit as shown, where it is engaged at its outer end by a clamping nut 36provided at its outer end with means for connecting it in an electriccircuit in eluding a battery 38. In the particular case hereillustrated, the wire 40 leading from the battery is attached tometallic plate 42 which is secured to the end' of nut 36 by an ordinaryscrew 44 in the obvious manner.

The-effective engine firing work of the plug is done through theelectricresistance coil 46 projecting from the end of the plug bodyinside. (as shown below) the engine wall 12. Member 46 is preferablymade in convenient conventional coil form with two terminal ends 48 and50. The first end 48 enters a perforation 52 formed for it in the bodyof plug body 16 and is detachably held in place by suitable set screw54. As the coil is grounded through this connection through the engine,no external electric wire connection is needed at this point. The otherend 50 of the'coil leads through a perforation 56 in core20-24 up toits'upper end as shown in the drawing where the turned over end 58 ofwire 50 is detachably clamped between the end of member 20 and anangular surface 60 inside nut 36.

\Vhen the parts are assembled as shown, current from the battery 38passes through members 40, 42 and 36 to the end 50 of the coil, andthence through end 48 to grounded body of the plug 16 and screw 54.\Vhen for any reason it is necessary to remove coil 46 for replacementor otherwise, the operator has only to remove the screw 54 and the nut36, whereupon after straightening up the end 58 of member 50 the coil isinstantly removable and a new one can be inserted in its place in theobvious manner. It will be noticed that core 2()-24 extends through theplug body 16 and thus supports, in an insulated manner. the resistancecoil 46-at the inside edge of engine wall 12.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is 1. An ignition plug having parallellongitudinal passages, and aresistance coil havin respective integralend portions straightened and extending in parallelism whereby movementof the coil in one direction will engage said end portions in respectivepassages and opposite movement of the coil will disengage the endportions from said passages, and means for releasably securing said endportions of the coil in said passages.

2. An ignition plug including a body portion. a core extending throughand insulated from the body portion, a resistance coil located at oneend of the plug, said plug body and core each having a longitudinalpassage therein, said passages respectively receiving the ends of saidcoil, and means for detachably securing the ends of the coil in saidpassages.

3. An ignition plug comprising a body portion," a core extending throughand insulated from the body portion, a resistance coil having one enddetachably secured to the body portion and its other end extendingthrough said core. said last mentioned end of the coil being bent intoengagement with an end of the core, and a clamping nut threaded on thecore and engaging the bent end of the coil to secure the same in place.

In witness whereof, I have hereunto subscribed my name in the presenceof two witnesses.

. ALFRED PETER.

\Vitnesses F. G. HOBART, B. H. ARNOLD.

